Mechanical performance of cylindrical and dual core pedicle screws in calf and human vertebrae

Lill, C. A.; Schneider, E.; Goldhahn, J.; Haslemann, A.; Zeifang, F.
November 2006
Archives of Orthopaedic & Trauma Surgery;Nov2006, Vol. 126 Issue 10, p686
Academic Journal
Failure of pedicle screws by loosening and back out remains a significant clinical problem. Pedicle screw fixation is determined by bone mineral density, pedicle morphology and screw design. The objective of this study was to compare the holding strength of newly developed dual core pedicle screws having a cylindrical design in terms of outer diameter and two cylindrical inner core regions connected by a conical transition with conventional cylindrical pedicle screws. Fifty bovine lumbar vertebrae and 40 human lumbar vertebrae were used. Five different screws were tested in nine experimental “settings” and ten specimens each. The screws were tested for cranial displacement and pullout strength before and after 5,000 cycles of cranio-caudal loading. The tests included a setting with fully inserted and 4 mm backed out screws. For statistical analysis the incomplete balanced block design was used. Cyclic loading led to a decrease of pullout force between 24 and 31% and a 9% increase of displacement. The cylindrical screw designs were affected more than the dual core designs. The pullout force of cylindrical screws was smaller than of dual core screws. Even in a backed out condition dual core screws showed a significantly smaller displacement than cylindrical screws. Pedicle screws with the dual core design provide good anchorage in the vertebra.


Related Articles

  • Minimally Invasive Multilevel Percutaneous Pedicle Screw Fixation for Lumbar Spinal Disease. Sang Gu Lee; Seong Son; Park, Chan Woo; Woo Kyung Kim // Journal of Spine;2013, Vol. 2 Issue 1, p1 

    Objective: There are rare reports on the result of multilevel (≥ 3 levels) percutaneous pedicle screw fixation (PPF). The purpose of this study was to report the clinical experiences for multilevel PPF of the lumbar spine. Methods: A total of 17 patients of lumbar spinal disease (7...

  • Which posterior instrumentation is better for two-level anterior lumbar interbody fusion: translaminar facet screw or pedicle screw? Hou, Yingnuo; Shen, Yong; Liu, Zhongpo; Nie, Zhihong // Archives of Orthopaedic & Trauma Surgery;Jan2013, Vol. 133 Issue 1, p37 

    Purpose: To determine whether translaminar facet screws can provide stability equivalent to pedicle screws and whether the two posterior instrumentations have the same influence on the adjacent segments in two-level anterior lumbar interbody fusion. Methods: In a biomechanical study conducted,...

  • Biomechanical study of rotational micromovement of the pedicle screw. Mizuno, Tetsutaro; Kasai, Yuichi; Sakakibara, Toshihiko; Yoshikawa, Takamasa; Inaba, Tadashi // SpringerPlus;7/8/2016, Vol. 5 Issue 1, p1 

    Background: In regard to the fixation using a pedicle screw (PS) and rod system, the mechanism from the onset of the clear zone up to the development of loosening of the pedicle screw is not completely clarified. The purpose of this study is to determine the cause of the pedicle screw loosening...

  • RADIOLOGICAL ANATOMY OF THE LUMBAR PEDICLES IN MALAY POPULATION USING REFORMATTED COMPUTED TOMOGRAPHY IMAGES. M., Abdullah; Shafie, Mohd; Y., Imran // Malaysian Journal of Medical Sciences;Jan2008 Supplement, p100 

    Objective: To obtain a database for the morphometry of lumbar pedicles from L1 to L5 of the normal Malay population treated in Hospital USM. Patients and Method: A cross sectional study on 136 Malay patients who were treated in Hospital Universiti Sains Malaysia.Patients divided into two groups...

  • Fundamental Anatomic Aspect To Safely Perform Pedicle Based Lumbar Spine Stabilization. Matuoka, Claudia Maria; Choi, Pil Sun; Basile, Roberto // Internet Journal of Minimally Invasive Spinal Technology;Supplement III, p31 

    An abstract of the article "Fundamental Anatomic Aspect to Safely Perform Pedicle Based Lumbar Spine Stabilization," by Claudia Maria Matuoka, Pil Sun Choi, and Roberto Basile is presented.

  • Acute Lumbar Burst Fracture Treated by Minimally Invasive Lateral Corpectomy. Amaral, Rodrigo; Marchi, Luis; Oliveira, Leonardo; Coutinho, Thiago; Pimenta, Luiz // Case Reports in Orthopedics;2013, p1 

    Burst fractures in acute spinal traumas are a difficult problem to solve. Different approaches and techniques have been utilized, but with high incidence of morbidity and mortality, besides unsatisfactory clinical and radiological results. Mini-open approaches recently emerged and have been...

  • Multilevel Direct Repair Surgery for Three-Level Lumbar Spondylolysis. Arai, Tetsu; Sairyo, Koichi; Shibuya, Isao; Kato, Ko // Case Reports in Orthopedics;2013, p1 

    A 45-year-old man presented to our clinic requesting evaluation for surgical treatment of chronic low back pain of more than 20 years duration. He was diagnosed with 3-level lumbar spondylolysis at L3-5. Direct repair using the pedicle screw and hook-rod system was conducted for all three...

  • The Use of Percutaneous Lumbar Fixation Screws for Bilateral Pedicle Fractures with an Associated Dislocation of a Lumbar Disc Prosthesis. Harrison, William D.; Harrison, David J. // Case Reports in Orthopedics;2013, p1 

    Study Design. Case report. Objective. To identify a safe technique for salvage surgery following complications of total disc replacement. Summary of Background Data. Lumbar total disc replacement (TDR) is considered by some as the gold standard for discogenic back pain. Revision techniques for...

  • Measurements of the lumbar pedicles in the Eastern Anatolian population. Kadioglu, H. H.; Takci, E.; Levent, A.; Arik, M.; Aydin, I. H. // Surgical & Radiologic Anatomy;May2003, Vol. 25 Issue 2, p120 

    Pedicle screw fixation of the spine has become one of the most stable and versatile methods of spine fixation, and knowledge of pedicle morphology is crucial for the safe application of these systems. We undertook this study because only a few reports have investigated Eastern populations....


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics